RevitalizationofRivers In IndiaDraftPolicy Recommendation undertaken by many Panchayats of Malappuram District, Kerala during the period 2009-2011. These results were also presented at the above conference. 3. UNIQUE CHARACTERISTICS OF VETIVER GRASS (Paul Truong; Tran Tan Van; Elise Pinners, 2008) a. Morphological characteristics: • Dense and finely structured root system • These roots have a mean tested tensile strength of about 75 Mega Pascal (MPa), which is equivalent to 1/6 of similar mild steel reinforcement. It also offers a shear strength increment of 39% at a depth of 0.5m (1.5 feet). • Roots grow very fast • Some varieties (like VS1) have a rooting depth of 3-4 m, which can be achieved in the first year itself • Stiff and erect stems that can stand relatively deep water flows • Tenaciously binds the soil and is difficult to dislodge • Highly resistance to pests, diseases • A dense hedge is formed when planted close together acting as a very effective sediment filter and water spreader. • New shoots develop from the underground crown making vetiver resistant to fire, frosts, traffic and heavy grazing pressure. • New roots grow from nodes when buried by trapped sediment. Vetiver will continue to grow up with the deposited silt eventually forming terraces, if Annexures 597

RevitalizationofRivers In IndiaDraftPolicy Recommendation trapped sediment is not removed. b. Physiological characteristics • Tolerance to extreme climatic variation such as prolonged drought, flood, submergence. • Extreme temperature resilience – from -14 o C to +55 o C . • Ability to re-grow very quickly after being affected by drought, frosts, salinity and adverse conditions after the weather improves or soil ameliorants added. • Tolerance to wide range of soil pH from 3.3 to 12.5 without soil amendment. • High level of tolerance to herbicides and pesticides. • Highly efficient in absorbing dissolved nutrients such as Nitrogen, Phosphorus and heavy metals in polluted water. • Highly tolerant to growing medium high in acidity, alkalinity, salinity, sodicity and magnesium. • Highly tolerant to Aluminium, Manganese and heavy metals such as Arsenic, Cadmium, Chromium, Nickel, Lead, Mercury, Selenium and Zinc in the soils. c. Ecological characteristics • It is intolerant to shade. Shading will reduce its growth and in extreme cases, may even eliminate vetiver in the long term. • In an open environment, weed control may be needed during establishment phase. • On erodible or unstable ground, vetiver first reduces erosion, stabilizes the erodible ground (particularly steep slopes), then because of nutrient and moisture conservation, improves its micro-environment so other volunteered or sown plants can establish later. Because of these characteristics vetiver can be considered as a nurse plant on disturbed lands. d. Adaptability Range • pH: 3.3 to 12.5 598 Annexures